A European drugmaker has closed a round of mezzanine financing to support its program to develop drugs for rare diseases.

Basel, Switzerland-based Therachon said Thursday that it had raised the $60 million mezzanine financing, led by Novo Holdings, with participation from new investors Cowen Healthcare Investments, Pfizer Ventures and funds managed by Tekla Capital Management. Also participating were existing investors Versant Ventures, OrbiMed, Bpifrance and Inserm Transfert Initiative. The company had closed a Series A funding round worth $40 million in January 2017, which included founding investors Versant Ventures and Inserm Transfert Initiative, along with OrbiMed as an existing investor and new investor Bpifrance.

Therachon’s lead drug candidate is TA-46, which it is developing for achondroplasia, the most common form of disproportionate short stature. It is described as a protein therapeutic that will be used as a weekly subcutaneous injection for children and adolescents with the disease. The company plans to advance TA-46’s development while expanding its rare disease drug pipeline.

The company is conducting a randomized, placebo-controlled, double-blind Phase I study of TA-46 in healthy volunteers to assess the drug’s safety, tolerability and pharmacokinetics of various dose levels. The company also started a natural history study to assess the burden of complications of achondroplasia in about 200 children from the US, Canada and Europe, which itself will enable the company to start treatment studies in children who have the disease starting next year. The Phase I study started in February and is planned to enroll about 70 patients, all in the Netherlands, according to a company announcement. The Dreambird study started in June.

In achondroplasia, the activated receptor that is normally eliminated remains “on,” thereby inhibiting normal bone growth, due to a mutation in the gene FGFR3 that causes the gene to send persistent growth-inhibition signals, thereby preventing its down-regulation, according to the company. The disease affects approximately 1-in-25,000 live births, and the only treatment available is limb-lengthening surgery. The Food and Drug Administration and European Medicines Agency granted TA-46 orphan drug designation in June 2017.

ClinicalTrials.gov, the National Institutes of Health-run database of clinical studies, currently lists 13 studies for achondroplasia. Several of the studies involve BioMarin’s BMN 111, which is also known as vosoritide. Meanwhile, Danish drugmaker Novo Nordisk has two studies listed, both taking place in Japan, that investigate the efficacy and incidence of adverse drug reactions among achondroplasia patients receiving Norditropin (somatropin). Therachon investor Novo Holdings is the investment arm of Novo Nordisk.